A data collator dynamically assembles individual samples into training batches and can apply batch-level preprocessing, such as padding. In a language-model fine-tuning pipeline, it connects prepared datasets with the training loop while keeping batch construction consistent. section 10.2.2
GPT-2 fine-tuning
Create a DataCollatorForLanguageModeling with the tokenizer and mlm=False, then pass it to Hugging Face Trainer alongside the model, training arguments, and training and evaluation datasets. The batch size should reflect available GPU RAM; single-digit values provide a practical starting point when monitoring out-of-memory errors.
